The proposed work constitutes an investigation of the origin, chemical nature, and properties of an anorexigenic substance found in the urine of animals and man, with especial attention to FMS 1A, the anorexigenic substance of rat urine. Various biochemical methods, principally column chromatography and polyacrylamide gel electrophoresis will be used to purify this material and to investigate its chemical components or oligomers. The effects of long-term injection of purified material will be studied in rats primarily to determine whether it has continuous appetite-suppressing activity and to investigate possible side effects involving hormone release or functions of the hypothalamus other than appetite control. Nutritional studies will be aimed at learning the effects of differing dietary proportions of protein, carbohydrate and fat upon excretion of urinary anorexigenic substance in rats, following up previous findings that a diet proportionately high in protein caused substantial increases in the amounts of rat urinary anorexigen produced. The source of the anorexigenic material will be investigated, with the first step being a careful reinvestigation of the question of the necessity of the pituitary gland in order for this material to be released into the urine.